Important Questions for Class 11 Biology- Structural Organisation in Animals

Animals are made up of different types of cells. Different organisms have different structural organizations. The different cells combine to form tissues. A number of tissues together form an organ, and different organs collectively form an organ system. The different types of tissues include- epithelial tissue, connective tissue, skeletal tissue, muscular tissue, and neural tissue.


Q.1. Which sugar is present in milk? How many monosaccharide units does it contain?
A.1. Lactose, a disaccharide sugar is present in milk. It consists of two monosaccharide units- D-glucose and D-galactose.
Q.2. Which linkage connects the monosaccharide unit in a polysaccharide?
A.2. ꞵ- 1,4’-glycosidic linkage
Q.3. Name an invert sugar. Why is it called so?
A.3. Sucrose is an example of invert sugar. It is called an invert sugar because the hydrolysis inverts the rotation of plane polarized light.
Q.4. What are the conditions when glucose is converted into gluconic and saccharic acid?
A.4. When glucose is oxidised with mild oxidising agents such as Br2 and water, it is converted into gluconic acid. When oxidised with strong oxidising agents such as HNO3, glucose is converted into saccharic acid.
Q.5. Match the following:

Column I Column II
Compound epithelium Alimentary canal
Compound eyes Cockroach
Septal nephridia Skin
Open circulatory system Mosaic vision
Typhlosole Earthworm

A.5. Compound epithelium- Skin Compound eyes- Mosaic vision Septal nephridia- Earthworm Open circulatory system- Cockroach Typhlosole- Alimentary canal
Q.6. Mention the cellular components of blood.
A.6. Blood contains the following components:

  • Plasma
  • Red Blood Cells
  • White Blood Cells
  • Platelets

Q.7. State the functions and types of nephridia in an earthworm.
A.7. Functions:

  • It regulates the composition and volume of body fluids.
  • It starts as a funnel that collects excess fluid from the coelomic chamber.
  • It connects to the tubular parts of nephridium and the waste is delivered to the surface through a pore.

Types of Nephridia:

  • Septal nephridia
  • Pharyngeal nephridia
  • Integumentary nephridia

Q.8. Mention the functions of each of the following:

  1. Ureters in frog
  2. Malphigian tubules
  3. Bodywall in earthworm


  1. Ureters in frog– Ureters carry sperms and excretory waste to the cloaca. They also carry the ova.
  2. Malphigian tubules- Each tubule is lined by glandular cells and carries out excretion. The glandular cells absorb the excretory materials which are then converted into uric acid. It is then released out through the hindgut.
  3. Bodywall in Earthworm– The body wall comprises of basal cells, receptor cells and gland cells. The body wall provides support and the cells secrete mucus to keep the skin moist. The muscles provide strength and rigidity.

Q.9. Give a brief account of the circulatory system of earthworm.
A.9. The earthworm has a closed circulatory system. It consists of capillaries, blood vessels and heart. The blood is confined to heart and blood vessels due to the closed system. The smaller blood vessels supply the gut, body wall and nerve cord. The 4th, 5th, and 6th segments comprise of blood glands that produce blood cells and haemoglobin which dissolves in the plasma.
Q.10. Where are the following found in the animal body?

  1. Chondrocytes
  2. Axons
  3. Ciliated epithelium


  1. Chondrocytes- These cells are found in the cartilage of the connective tissue and secrete matrix.
  2. Axons- It is a long fibre with a long distal end. There is a bulb-like structure called synaptic knob at the end. Axons transmit nerve impulse away from the cells.
  3. Ciliated epithelium- They help in the movement of particles or fluid over the epithelial surface in structures such as the trachea, nasal cavities, bronchial tubes.

Q.11. What are the different cell junctions found in tissues?
A.11. The following cell junctions are found in tissues:

  • Tight Junctions- The plasma membrane of adjacent epithelial cells are held close to each other.
  • Gap Junctions- They facilitate the exchange of chemicals between adjacent cells.
  • Adhering Junctions- They help in connecting the neighbouring cells together.

Q.12. How are frogs beneficial for mankind?
A.12. Frogs feed on insects and protect the crops. They are an important link to the food chains and the food web in the ecosystem. Their legs are also a source of food.
Q.13. Where are the hepatic caeca in a cockroach located? What is its function?
A.13. The hepatic caeca are present at the junction of foregut and midgut. It secretes digestive juices and helps in digestion.
Q.14. Give two identifying features of an adult male frog.
A.14. Following are the features of an adult frog:

  • The loose skin folds on the throat of a male frog known as vocal sacs. They produce a croaking sound.
  • Nuptial pads are copulatory pads present on the forelimb of the male frog. These help in closing the female during amplexus.

Q.15. Answer in one line:

  1. What is the common name of Periplaneta americanaa?
  2. Where are the ovaries in a cockroach located?
  3. How many spermathecae are present in an earthworm?
  4. How many segments do the abdomen of cockroach contain?


  1. Cockroach
  2. 4th, 5th, and 6th abdominal segments
  3. Four pairs of spermathecae in the 4th, 5th, and 6th abdominal segments.
  4. 3-7 segments

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Also Acess Class 11 Biology Sample papers 

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